Coffee maker



Oct. 9, 1945..y F. E. woLcoTT COFFEE MAKER Filed Feb. 17, 1943 I.INVENToR. A Fim/ME WoLcoTT. BY

'Patented Oct. v9, -1945 COFFEE MAKER Frank E. Wolcott, West Hartford,Conn., assignor to The Silex Company, Hartford, Conn.

Application February 17, 1943, Serial No. 476,196

i Claim.

y This invention relates to coffee makers and more particularly to thoseof the vacuum type'.

It is well known that the efficiency of vacuum type coffee makersdepends materially upon the allowance of a proper amount of time for theliquid in the upper bowl of the coffee maker to becomeinfused with thecoffee grounds therein .before it returns to the ,lower bowl as coffee.It has been found that when liquid, or hot water. is permitted to flowfrom the upper into the lower bowls in too short a time, an insuicientamount of infusion will have taken place, resulting in a weak coffeebrew and the waste of coffee, because more coffee grounds will berequired to produce a brew of a certain desired strength. On the otherhand, if the water is 'allowed to remain in the upper bowl for too longa time, an excessive amount of infusion will take place and this willextract undesirable elements from the coffee and result in a coffee brewof poor quality.

It is an object of the invention, therefore, to provide a coffee makerhaving improved ltering means which will permit the liquid to remain inthe upper bowl for the correct amount of time, so as to produce a coffeebrew containing the maximum amount of the good qualities of the coffeewithout any of the undesirable quali ies and which is produced from theminim m amount of coffee necessary for the strength of brew desired. y

A further object of the invention, is to provide such a coffee maker ofimproved construction whereby it is rendered more efficient initsoperation.

A still further object is to provide novel filtering means, for vacuumtype coffee makers, which will retard the flow of liquid from the upperY bowl of such a coffee maker to thereby insure more efficient operationand permit proper infusion of the liquidwith the coffee grounds so thatbetter coffee will result.

Further objects and advantages of my invention w-ill be more clearlyunderstood from the following description and from the accompanyingdrawing in which: g

Fig. 1 is a view, in central vertical section, of a coffee makerembodying my invention.

Fig. 2 is a side view of the drainer member used in said coffee maker.

Fig. 3 is a bottom view thereof.

Fig. 4 is a flat view of the strainer member used in my invention.

As illustrated in the drawing, the numeral l denotes the lower bowl ofthe coffee maker which is preferably made of glass and has a neckportion E with a flared mouth portion 1; a handle B being preferablysecured to said neck portion by means of a suitable band 9.

An upper bowl Ill is mounted upon the said lower bowl and has a stem IIdepending thereinto. The said stem is provided with a sealing collar I2which fits between the said stem and the inner surface of the neckportion 6 and supports the upper bowl upon the lower bowl.

vIn the preferred construction shown, the said upper bowl is provided atthe bottom thereof with a depression I3 having an annular shoulder I4which surrounds the interior of the stem II and provides an abutment forthe upper end of the seal I2. Ii' desired, the said stem II may also beprovided with projections I5 for retaining the seal in position thereon.

`My improved filter member comprises an imperforate disc portion I6having a handle IG-a. The said member is preferably provided with anannular lipl orv depending flange Il, along the peripheral edge of thebottom thereof, and an axial projection I8 also depending from saidbottom; the said ange I1 thereby forming an annular recess I9 whichsurrounds the said extension.

A strainer member, preferably in the form of a disc 20 having a centralopening 2 I, 1s positioned between the said filter and the shoulder Iand extends upwardly between the inner wall of the recess I3 and theouter edge of the disc portion of said filtermember with the projectionIB extending through the opening 2 I.

The projection I8 is tapered to permit the same to be forced into theopening 2| and provide a tight fit for the strainer, around theprojection, which will prevent leakage of coffee grounds into the lowerbowl.

It will be noted that a marginal portion of the strainer disc fitsclosely between the'peripheral edge of the drainer member and theslightly tapered wall of the recess i3. thereby retained in verticalposition, as at 22, so that the water, on its return from the upper intothe lower bowl, must pass edgewise through the marginal portion of thestrainer;

When the operation of my improved coffee maker is initiated, water iscontained in the lower bowl and coffee grounds in the upper bowl. As theWater is heated, expansion of the air in the lower bowl will force thewater upwardly through the stem II and into the upper bowl where itbecomes infused with the coffee grounds therein. When the heat isremoved from the lower bowl, the air therein will condense and form avacuum that will cause the water from the upper bowl to This portion isreturn into the lower bowl. During the movement of the water into theupper bowl, it will be forced through the strainer member 20. After thelower bowl hasrbeen removed from the heat, the return of the water intothe lower bowl will be delayed by the fact that the drainer member isimperforate and the said water can ilow only edgewise through the marginof the strainer 20, which is disposed between the drainer member and thesurfaces of the recess i3 and the seat Il. Therefore, since the watermust ow through the strainer disc material in an edgewise direction,rather than crosswise, as has heretofore been common in such devices,maximum filtration will be provided while, at the same time, the passageof the water through-the strainer member will be retarded and therebypermit more time for the infusion of the coffee in the upper bowl.

It has been found that my improved coee maker, due to the particulardisposition of the strainer member, which will cause the water to flowedgewise therethrough, and the impermeability of the lter member, willpermit the water to remain in the upper bowl for just the -length oftime which is required for an infusion which will extract the maximumamount of the good qualities in the coffee grounds without any of theundesirable qualities. This, therefore, also prowasting of the desirablequalities in the coffee grounds which would otherwise remain unused ifthe water were allowed to lter too rapidly through the strainer on itsreturn into the lower bowl.

It is pointed out that the shoulder Il and the annular rib Il arepurposely made narrow so as to control the distance for which the waterhas to pass through the strainer material and thereby avoid too long adelay and provide the proper period of time for the infusion. Further,

the annular recess I9 prevents contact between that portion of thesurface at the lower side oi the drainer member I6 and the surface ofthe strainer 28. This will assure the application of the entire weightof the drainer member upon that portion of the area of the strainerwhich is disposed between the shoulder Il and the annular rib I1 of thedrainer member.

I claim:

For a coffee maker of the character described, a` lter member includinga disc shaped portion of imperforate material having an axial projectiondepending from the bottom thereof, an an;v nular peripheral invertedshoulder in said bot- `to'm'spaced from and surrounding said projection,

and a strainer member comprising a disc of pervious material having acentral opening and surrounding said projection and extending along thebottom of said drainer and upwardly along the sides thereof.

. FRANK E. WOLCOTT.

